Isolation of C-type viruses from cell cultures of systemic lupus erythematosus (SLE) is being attempted using chemical induction and cocultivation with subculturing for prolonged periods and viral detection by reverse transcriptase assay of the culture supernatants. Papovavirus antibodies are being measured in SLE and control sera. Cell-mediated immunity to measles will be measured in SLE lymphocytes using H3-thymidine incorporation.